Tension oscillation in arteries and its abnormality in hypertensive animals

1. The mechanisms of oscillatory contraction of arterial smooth muscle in v itro are discussed. 2. The membrane potential and cytoplasmic free Ca2+ concentration in smooth muscle cells oscillate in the presence of agonists. 3. The oscillatory change in the membrane potential of smooth muscle cells is related to Ca2+ release from intracellular stores. 4. Gap junctions between smooth muscle cells play important roles in the sy nchronized oscillation of the cytoplasmic free Ca2+ concentration in this p opulation of cells. 5. Endothelial cells may increase or decrease the tension oscillation of sm ooth muscle cells. 6. In arteries from hypertensive rats, an increase in membrane excitability and the number of gap junctions between smooth muscle cells and impaired e ndothelial function are the main factors responsible for the modulation of tension oscillation.